21945349 has 4 divisors (see below), whose sum is σ = 21958636. Its totient is φ = 21932064.

The previous prime is 21945347. The next prime is 21945367. The reversal of 21945349 is 94354912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10432900 + 11512449 = 3230^2 + 3393^2 .

It is a cyclic number.

It is not a de Polignac number, because 21945349 - 2¹ = 21945347 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21945347) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3744 + ... + 7609.

It is an arithmetic number, because the mean of its divisors is an integer number (5489659).

Almost surely, 2^21945349 is an apocalyptic number.

It is an amenable number.

21945349 is a deficient number, since it is larger than the sum of its proper divisors (13287).

21945349 is a wasteful number, since it uses less digits than its factorization.

21945349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13286.

The product of its digits is 38880, while the sum is 37.

The square root of 21945349 is about 4684.5863211174. The cubic root of 21945349 is about 279.9717190824.

The spelling of 21945349 in words is "twenty-one million, nine hundred forty-five thousand, three hundred forty-nine".